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baub
22:15:39 Wed
Jan 22 2014

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12 volt DC Magnetic separators

Has anyone have info on these small mag separators?
Do they work well?
Who makes them etc.

Tnx,

b

  
JOE_S_INDY
23:52:12 Wed
Jan 22 2014

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Re: 12 volt DC Magnetic separators

Bob,

The time, money and experimentation to get just the right amount of electro-magnetism for just the right time interval is really, really hard to do.

Were it I, I would just grab the right Gold Hog mats, learn from the videos just how much water and velocity to use and process those lighter materials right through the sluice and out the end. Hematite and Magnetite are in the SG 5.12 - 5.28 range and, given some good riffle science really are pretty easy to get to pass over the mats, leaving the Gold behind.

http://www.goldhog.com/gold_prospecting_forum/

My thoughts zero on fast, easy, simple and no moving parts.

Joe



---
Wiser Mining Through Endless Personal Mistakes
 
 
baub
03:03:17 Thu
Jan 23 2014

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Re: 12 volt DC Magnetic separators

Thanks Joe, I'll give it a looksee.
It's snowing again and too cold to do samples. I thought I'de look for a simple way to remove the mags before tabling and reduce the number of passes on the table. It's an RP-4 with the spinning magnets, but it still takes a few additional passes to capture the mags. I usually don't mind as I make small cuts only, but one area I'm going to frequent more often has a large tails pile with abundant black sand that would take a lotta passes to eliminate the b/s.
The Gold Hog mats might work good, especially in a controlled environment. Maybe in the future if the b/s's are rich and extensive enough.

Keep snug and thanks again,

b

  
geowizard
17:41:53 Thu
Feb 6 2014

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Re: 12 volt DC Magnetic separators

Is it against the law?

There are laws that control DIY electromagnets!

You can start like I did. In 6th grade, I took a large nail and wound about 20 turns of my dads blasting wire around it. I connected a dry cell (1.5 volt) battery. It worked!

You can go to the hardware store and legally buy a section of iron pipe. You will need some wire. You can buy wire from a local electric supply or electronics store.

You must obey certain laws!

The laws are the laws of physics. One of those laws is called "Ohms Law".

First, consider the magnetic force you wish to create.

The force is calculated in ampere-turns. Force = amperes x turns.

Wrap "turns" of wire around the pvc pipe. The more turns, the more electromagnetic force. Since you aren't sure how much force you need, take some black sand and use it to test your electromagnet.

I would buy some 12 AWG (14 AWG if you can find it) insulated wire. Wrap 50 turns around a section of 1" PVC pipe.

You need a battery. You could use a 12 volt battery. You can buy different sized 12 volt batteries at Ace Hardware. I personally like the UB1250 non-spillable, sealed, lead-acid batteries. You might also pickup a charger.

The UB1250 is a 5 amp-hour battery. It will produce 5 amps for one hour or 1 amp for 5 hours for example.

So, if we set up a 1 amp circuit, we need to control the current to obtain one amp of current. If we just hook up the battery to the coil, then it will probably get very hot and melt down into a real mess.

When the coil is wound, I usually drill a couple of holes in the PVC pipe to put the wire through to keep the windings from unraveling.

So, next, comes Ohms Law. Ohms law says that the current equals the voltage divided by the resistance.

We know the voltage is 12 volts.

We get an ohm meter i.e. a digital multi-meter and measure the resistance of the coil. There are also tables that will tell you how much resistance is in one foot of 12 AWG copper wire. You can look it up online and figure out the resistance of your coil.

12 AWG wire is designed to handle 20 amps of current. To be safe, it is good to set a lower limit for current. You might try it at 5 amps or 10 amps.

So, for a 5 amp series circuit, volts divided by current will give the required resistance.

A six amp circuit would = 12 volts/6 amps = 2 ohms of resistance. If the coil is 1 ohm, you need to add another one ohms of resistance in series to limit the current to 6 amps. You buy or make power resistors to limit the current.

Not really too complicated.

Edit- Make it using "iron" pipe.

- Geowizard
[2 edits; Last edit by geowizard at 15:23:12 Mon Feb 10 2014]

  
geowizard
17:49:13 Thu
Feb 6 2014

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Re: 12 volt DC Magnetic separators

Another thought,

You could make two - one ohm coils and have twice as much electromagnet. That way, it picks up twice as much black sand! :smile:

Cost is $4.00 instead of $2.00.

- Geowizard
[1 edits; Last edit by geowizard at 17:49:34 Thu Feb 6 2014]

  
baub
19:59:20 Thu
Feb 6 2014

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Re: 12 volt DC Magnetic separators

This dovetails with my earlier experience as a radar tech and later employment in the steel industry as an electronics tech. About 25 years total.
I've seen pix of over the belt mag systems and it would seem to be the way to go. No impediment to the flow as the magnetic particles go straight up, more or less.
There's a couple of elderly rheostats in the pole barn that might suffice as intensity/current controls. Maybe a knife switch from one of my hi current battery chargers too. Even a battery or two from my semi, which is semi-retired at the moment. Combine that with an key-start jaw crusher nearby
for a charger and tada, magnets with attitude!

b

  
geowizard
23:50:45 Sat
Feb 8 2014

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Re: 12 volt DC Magnetic separators

baub,

Now you're cooking!

I don't know how many pounds of black sand you are contending with. The system would only need to be sized according to the feed.

The magnet could be raised for cleaning - i.e. to place a tray under it and out of the water flow.

- Geowizard

  
baub
01:45:22 Sun
Feb 9 2014

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Re: 12 volt DC Magnetic separators

It would be small at first. Both to perfect the system and second I don't have a lot of b/s now, (my friends may say otherwise) but may in the future.
I've priced a few conveyor head rollers with magnetic capabilities, so there's another idea. I need to build another belt conveyor anyway. For the meantime maybe a DC electromaggie would work.

b

  
geowizard
15:33:27 Mon
Feb 10 2014

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Re: 12 volt DC Magnetic separators


There are trade-offs to consider...

With reference to using a 12 volt battery, As was mentioned above, magnetic force = current multiplied times the number of windings. The conclusion would be that you wrap a coil with a zillion windings!

The more turns you wind on the coil, the longer the wire. The longer the wire, the more resistance. As you double the windings, you double the resistance. Doubling the resistance cuts the current in half. So, there is an optimum number of windings at which the current is nominal for the application.

Otherwise, the electromagnet needs a larger voltage supply. At that point, you can add batteries in series to increase the voltage. Two 12 volt batteries in series will produce twice as much current.

- Geowizard

  
baub
15:53:22 Mon
Feb 10 2014

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Re: 12 volt DC Magnetic separators

Gotcha. Thanks Geo.

  
geowizard
17:00:13 Mon
Feb 10 2014

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Re: 12 volt DC Magnetic separators

Note:

My earlier post has been edited to suggest "iron" as a form to wind the electromagnet on. Iron provides more concentration of the magnetic flux.

A magnet wound on iron strap can have extensions that form any desired shape. For example, a rectangular shape with a gap at the bottom.

As a matter of possible interest:

Black sand is composed of different types of iron and related minerals. The amount of magnetic intensity controls the types of minerals that are attracted.

- Geowizard
[1 edits; Last edit by geowizard at 17:00:59 Mon Feb 10 2014]

  
overtheedge
20:02:01 Mon
Feb 10 2014

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Re: 12 volt DC Magnetic separators


Quote: geowizard

Two 12 volt batteries in series will produce twice as much current.


No sir. In series you twice the voltage. In parallel gets you twice the current draw available (AH).

The reason for using higher voltages in electromagnets is to counter resistance losses. As you pointed out, the wire has resistance. Ohms law E=IR where E is voltage, I is amperage and R is resistance in Ohms. If the voltage is low, you spend money to turn your electromagnet into a electric space heater. W = IČR where W is watts. The key is to use a high enough voltage that resistance losses are acceptable, but doesn't exceed the break-down voltage of the wire insulation.

eric

  
geowizard
20:54:01 Mon
Feb 10 2014

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Re: 12 volt DC Magnetic separators

eric,

Two 12 volt batteries (in parallel) doubles the current "capacity". Not the current.

Current = Volts/Resistance.

Double the volts = double the current! :smile:

Here's an example:

12 volts and 2 ohms;

Current = 12 / 2 = 6 Amps

Two 12 volt batteries in series = 24 volts.

Current = 24 / 2 = 12 Amps.

We agree on capacity. Two 12 volt 100 amp-hour batteries in parallel doubles the capacity to 200 amp-hours. So, you can operate the electromagnet twice as long. Lets use another example.

One 12 volt 100 amp-hour battery would provide 10 amps for 10 hours. Two 100 amp hour batteries in parallel would provide 10 amps for 20 hours.

- Geowizard
[1 edits; Last edit by geowizard at 20:59:07 Mon Feb 10 2014]

  
overtheedge
00:37:24 Tue
Feb 11 2014

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Re: 12 volt DC Magnetic separators

Aha, the problem appears to be in the phrasing.

It is the load that determines the current draw, not the number of batteries in series. No load, no current draw.

You are correct about double the voltage and the load will draw twice the current. However, each battery continues to produce the same voltage and current singly or in series as long as the load remains constant.

Perhaps I'm a bit of a stickler, but here is a classic example of both of us understanding yet confusion still happened.

I stand corrected on the rest of my previous post. I tend to evaluate circuits based upon the amount of work required. I contend any power consumption above what is required is just electrical space heating.

I'd better shut up now. No sense me adding any more confusion.

eric

  
geowizard
16:15:27 Tue
Feb 11 2014

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Re: 12 volt DC Magnetic separators


I WAS scratching my head a little!

Good follow-on though.

It is all about work. How much energy is required?

Power (in Watts) = volts times current.

So, a more powerful magnet requires more power! Leave it to Geo to figure that out!

Ok, so, where does the power come from? One of the trade-offs is...

How much work will it take to reduce the work? :confused:

Because there is always inefficiency in conversion of energy, it will take more energy than is saved.

The objective would be to find free energy. One source would be solar power. But, solar panels are not free.

Another source would be hydro-electric power. Generators are not free either.

Has anyone thought about placing a paddle wheel in their sluice box to generate electric power?

I didn't think so.

- Geowizard

  
Rod_Seiad
16:20:43 Tue
Feb 11 2014

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Re: 12 volt DC Magnetic separators

Good stuff guys. Miners know how to use electricity, if it's available.

We need some more of it however. There doesn't appear to be enough to get the work accomplished which miners are after. Imagine a massive Tesla power generation unit. The Earth would be the nearby miner's storage battery.

It seems to me....with the correct electrical engineering and supply......gold could be extracted from Earth without the need for moving mountains. We could re-liquify AU and draw it into catchment devices. Sorta reverse gravity based on static electricity.

  
dickb
19:12:20 Tue
Feb 11 2014

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Re: 12 volt DC Magnetic separators

Question here?
Why would you want to use a electromagnet and pay fuel costs to run it, when permanent magnets will work just as well for free operating costs once the person buys the permanent magnet?

Dickb

  
baub
21:42:16 Tue
Feb 11 2014

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Re: 12 volt DC Magnetic separators

My thoughts are to be able to control the amount of attraction and to be able to turn it off to release the captured material when you want or need to.
A simple battery, rheostat, magnet and switch would be enough to do this in the field. Mass reduction at the point of capture would mean less cons to lug out at the end of the day, no matter if they are reduced via electromags or good old permanent mags. The drawback is the heavy batty. If you have atv access you can run the e'mags from that or just take them to camp to process.
Frinstance, my cons usually have strongly magnetic materials like magnetite, raw iron and some other hi-iron content particles along with ilmenite and less strongly magnetic junk that require higher field strength mags to capture. These hi-test mags can be a problem in them selves as they will stick to a lot of stuff. These babies are super for ilmenite etc.
If you are encamped someplace nearby your capture area, then you can recharge the battys by any number of sources.

b





  
shaftsinkerawc
21:25:00 Wed
Feb 12 2014

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Re: 12 volt DC Magnetic separators

Would a house trailer Axle brake puck be strong enough for what you're trying?

  
baub
15:33:00 Thu
Feb 13 2014

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Re: 12 volt DC Magnetic separators

It might at that. The worst it could do is remove the iron. Mounted over a sluice, with an easy way to adjust the height and for quick cleanup removals, it might be the way to go.

b

  
rabbitt46
17:30:37 Fri
Feb 14 2014

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Re: 12 volt DC Magnetic separators

Has anyone thought about placing a paddle wheel in their sluice box to generate electric power?

I didn't think so.

- Geowizard

Seems like it would work with a small wheel on the outflow of a sluice, if its to recharge the battery while running material.
:confused:

  
baub
21:50:42 Fri
Feb 14 2014

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Re: 12 volt DC Magnetic separators

Hi Rabbit,

It might work if you put it past the end of the sluice, much lower to make enough drop to generate enough power to be useful. Picture the old style water mills.
12 volts and 1 amp figure up as 12 watts.
You might need another open, no carpet, sluice to concentrate the flow and aim it towards the vanes of the generator.

b

  
rabbitt46
15:41:34 Sat
Feb 15 2014

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Re: 12 volt DC Magnetic separators

I know that the flow coming off my 3" high banker would be enough to turn a small wheel. Not referring to a heavier pelten wheel but something lighter like the squirrel cage blower out of a 12 volt motor.
If there was a way to reverse the flow of power in the motor it could be the charger for a battery.:
smile:

  
geowizard
17:03:30 Sat
Feb 15 2014

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Re: 12 volt DC Magnetic separators


Permanent magnet DC motors will generate power.

Rotating windings in a magnetic field - it's a generator!

- Geowizard

  

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